Search Results

The importance of MMF space harmonics in squirrel-cage induction motors has been recognized in the literature since the beginning. Their details have been analyzed over the years, but only partly systematized. In this article, however, not only the origin and the entire system of that harmonics are described, but also their interaction causing the asynchronous…

With the spread of inverters, the attention of designers naturally turned to 5-phase motors, due to their advantageous properties. In this regard, perhaps the most important issue in the design of such machines is the selection of the correct rotor slot number. Many articles have been published on multiphase machines, however, only few of them…

Skewing of the rotor slot of a squirrel-cage induction machine has been commonly used since the beginning. However, little guidance is given regarding the principle of the working effect of the method, but even in such rare cases, the explanation does not cover the true physical reality. Consequently no formula exists for calculation of the…

This article presents a roadmap for distribution grid µPMU hardware and software design consideration and implantation to ensure high performance within limited computational time of sampling frequency 512 samples/cycle. A proposed 12 channels, multi-voltage level µPMU hardware and rules of voltage and current transducer, analog filter, analog-to-digital converter, sampling rate definition, and PCB design and…

In this paper, second order generalized integrator (SOGI) is discretized to design the control algorithm of unified power quality conditioner (UPQC). A UPQC is combination two voltage source converter (VSC) and VSC are connected with back to back DC link. The first one VSC is in series to maintain the desire voltage at point of…

The paper presents the technique for the user-friendly numerical simulation of coupled oscillators described by the Kuramoto model. Oscillators couplings are defined as arbitrary 2?-periodic functions given by the Fourier series. Matlab procedure was developed to generate netlist for the equivalent electrical circuit diagram of the Kuramoto model. The input data of the procedure include…

Distributed Solar Photovoltaic (DSP) Plants are one of the fastest growing renewable energy systems in South Africa. The primary components forming an integral part of the point of common coupling (PCC) are, the inverter used to convert dc voltage to ac voltage and step-up transformers which step-up low voltage input to the desired output level.…

This paper presents a new observer-based method which deals with the extraction of amplitude of characteristic frequencies for the fault diagnosis in permanent magnet synchronous motors (PMSM). First, a pilot survey is made to investigate the typical harmonics in the line currents of PMSM. Second, an appropriate structure of observer is formulated with the input…

Light Emitting Diode (LED) lamps are used as a replacement of “old-fashioned” or incandescent lighting sources, as they reduce the amount of energy consumed. As a side-effect of more efficient energy usage they produce electrical noise. This noise reduces the efficiency of information signal transfer when Power Line Communications (PLC) are used. This study focuses…

South Africa is aiming to achieve a generation capacity of about 11.4GW through wind energy systems, which will contribute nearly 15.1% of the country’s energy mix by 2030. Wind energy is one of the principal renewable energy determinations by the South African government, owing to affluent heavy winds in vast and remote coastal areas. In…

Manufacturing industry is facing several challenges in power quality and energy consumptions that play a significant role in the cost of goods sold in addition to the operational efficiency of manufacturing plants. The current techniques are not enough to manage the manufacturing processes from power perspectives as it is focusing only on the monitoring of…

This paper proposes a photovoltaic (PV) integrated shunt active power filter (SAPF) for reactive power compensation, uneven loading and compensation of harmonic current. The control of SAPF is implemented by using adaptive based current estimation algorithm to maintain power factor near to unity and source current sinusoidal at source side. The weights are calculated online…

This paper covers a new topology, a synchronous wind turbine generator, and a solar photovoltaic generator. The Permanent Magnet Synchronous Generator is linked to the grid by back-to-back voltage source converters (BtB VSC), consisting of a two-stage rectifier and a five-stage Neutral Point Clamped inverter, operated by the Space Vector Pulse Width Modulation technique. A…

Wind energy is emerged rapidly as the most important and viable sustainable power source due to the mature technology and wide availability. The integration of wind energy sources and utilization of nonlinear loads having different characteristics results in several challenges in a distribution system. One of which is power quality issue .Hence, in this work,…

Harmonic distortion is a problem that can be caused by the use of power electronic devices. The effect of harmonics has an impact on changes in the input voltage source waveform which is referred to as wave defects. This incident has an impact on electronic faults and overheating of the power transformer coil as a…

In fast charging station for Battery Electric Vehicles (BEVs) the three-phase PWM (Pulse Width Modulation) inverters generate parasitic Differential-Mode Voltages (DMV) and Common-Mode Voltages (CMV). Parasitic voltages are a side effect of using the width modulation to shape the phase-to-phase inverter’s voltage. In this article the authors present a mathematical description of the differential-mode (DM)…

In fast charging station for Battery Electric Vehicles (BEVs) the three-phase PWM (Pulse Width Modulation) inverters generate parasitic Differential-Mode Voltages (DMV) and Common-Mode Voltages (CMV). Parasitic voltages are a side effect of using the width modulation to shape the phase-to-phase inverter’s voltage. In this article the authors present a mathematical description of the differential-mode (DM)…

STATCOM a shunt connected Flexible Alternative Current Systems (FACTS) device using for fast control of voltage and reactive power control in the power grid. To optimize Nouakchott power system at 2030 year, we anticipate both generation and demand grow. A set of nonlinear equations are solved through Newton Raphson method and programmed in PSS/E and…

Requirement for pole-changing motors emerged at the very early times of asynchronous motor design. Different solutions have been elaborated and some of them are generally used. One of these solutions in use is the so called pole phase modulation method. The so called 3 Y / 3 Y pole-changing winding being subject of this paper…

Doubly fed asynchronous machines have an outstanding property: they can be operated up to twice rated speed delivering full rated torque. This paper presents, for the first time in the literature, a control system for multiphase asynchronous machines fed by Voltage Source Inverters (VSIs) both in stator and rotor that incorporates the harmonic torques. The…

A selective harmonic elimination system using fuzzy logic for the elimination of high magnitude harmonics with frequencies close to fundamental in the output voltage of single phase inverters is presented. The system does not require look up tables for storage of the data as in traditional harmonic elimination methods. The input of the fuzzy system…

This article examines the hydrogen storage phenomenon in a spherical cavity. The hydrogen gas or liquid is subjected to high pressures, leading to significant loss of mass of hydrogen, and requires materials that can withstand these high pressures also minimize losses. For all these reasons, the problem is considered at the quantum scale. So in…

High Frequency Signal Injection based techniques are robust and well proven to estimate the rotor position from stand still to low speed. However, Injected high frequency signal introduces, high frequency harmonics in the motor phase currents and results in significant Output Torque ripple. There is no detailed analysis exist in the literature, to study the…